Ductwork system

ABSTRACT

An insulated ductwork system particularly adapted for exterior use joins together pre-assembled air circulation duct sections that each have a ductwork passageway that is formed solely with insulation panels of foam insulation material disposed between foil sheets that are in turn covered by additional insulation material and an outer protective jacket to seal the ductwork from weather effects. The air circulation duct sections are used without traditional metal ductwork forming any part of the air circulation duct. Receiving flanges extend from the ends of each air circulation duct section and the duct sections are joined together in abutting relation with at least one slidably engageable sleeve that engages the flanges. A filler insulation is disposed over the sleeve. A closure band is disposed over the filler insulation and joined to exterior surfaces of the air circulation duct sections.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No. 14/072,932, filed Nov. 6, 2013, now issued as U.S. Pat. No. 9,371,941, the contents of which are incorporated by reference herein in their entirety.

FIELD OF THE INVENTION

The invention relates to a duct work design particularly suitable for exterior ductwork systems, in which the ductwork passageway is formed solely with insulation panels that are in turn covered by an outer protective jacket to seal the ductwork from weather effects.

BACKGROUND OF THE INVENTION

Heating, ventilation and air conditioning systems use ventilation air ducts installed throughout a building to supply conditioned air to a room through outlet vents, and ducts to remove air through return grilles. Galvanized mild steel is the standard and most common material used in fabricating ductwork. For insulation purposes, metal ducts may be lined with faced fiberglass blanket (duct liner) or wrapped externally with fiberglass blankets (duct wrap), or lined or wrapped with foams or other insulative materials.

Traditionally, air ductwork was made of sheet metal which was installed first and then lagged with insulation as a secondary operation. Aluminum tape was applied to all seams where the external surface of the aluminum foil had been cut. Internal joints then could be sealed with a sealant.

When used outside, the ductwork and insulation combined therewith require a weather tight seal. U.S. Pat. No. 6,360,783 discloses one improved duct work system in which insulating panels are applied externally around the metal duct. The insulating panels comprise two adjacent insulation panels. Then, an embossed metal layer extends over the outer surfaces of the outermost insulation panel. Adjacent insulating panels are joined by fasteners. The embossed metal layers overlap at some edges and are further joined by grout or adhesive to create moisture barriers at their overlapping edges and interfaces.

Ducting systems that use insulation panels to form the ductwork passageway without an inner sheet metal duct have been proposed for indoor use. Such systems lack stability and weather resistance necessary for exterior ductwork systems. Accordingly, improvements to ductwork systems and more weather-robust exterior ductwork systems continue to be sought.

BRIEF SUMMARY OF THE INVENTION

The present invention in a first aspect is directed to an air circulation duct section that has an inner duct air passageway formed with a first insulation material having a top wall, a bottom wall and two opposed sidewalls. The first insulation material is not a traditional sheet metal duct. Solid insulation is joined to the outer surfaces of the first insulation material of the inner duct air passageway. A jacket is joined to the outer surfaces of the solid insulation. The jacket may be formed from a series of sheet sections, such as aluminum sheet, with at least some of the sections having angled flange edges that overlap adjacent jacket sections. The flange edges may be joined with fasteners to the overlapped side edges of adjacent jacket sections. A sealant or grout may be applied to the flange edges, and may be held within ribs or channels formed in the flange edges.

In one embodiment, the first insulation material of the inner duct passageway may be a foam insulation disposed between foil sheets.

Alternatively, in another embodiment, the first insulation material may include multiple insulating panels adhered or laminated together.

Two or more air circulation duct sections may be joined together in end to end relation in a series to form an insulated ductwork system. The joint at which two air circulation duct sections meet may be covered by filler insulation and in turn by a closure band disposed over the filler insulation and the joint. The closure band may be joined to the jackets of the air circulation duct sections with adhesive tape, such as butyl gasket tape, in combination with fasteners, such as screws. In addition, the closure band may define ribs or channels at or near its side edges to receive sealant or grout to adhere longitudinal edges of the closure band to the jackets of the air circulation duct sections.

Advantages of the air circulation duct sections and ductwork system will appear from the drawings and following description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention described above will be explained in greater detail below on the basis of embodiments and with reference to the accompanying drawings in which:

FIG. 1 is a left front perspective view broken away showing one embodiment of a section of an air circulation duct system according to the invention in which two air circulation duct sections are joined together;

FIG. 2 shows a left front perspective view broken away showing two air circulation duct sections according to the invention prior to joining them together;

FIG. 3 shows a left front perspective view broken away showing the two air circulation duct sections according to FIG. 2 in a first step of joining the two sections together;

FIG. 4 shows a left front perspective view broken away showing the two air circulation duct sections according to FIGS. 2 and 3 in a second step of joining the two sections together;

FIG. 5 shows a cross-sectional view taken along line 5-5 in FIG. 1; and

FIG. 6 shows a cross-sectional view taken along line 6-6 in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning in detail to the drawings, FIGS. 1, 5 and 6 show two air circulation duct sections 10A and 10B joined together to form an air ductwork system passageway 100 for directing treated air in a heating, ventilation and/or air conditioning (HVAC) system. The air ductwork system passageway 100 may be used on both inside and outside installations. Each air circulation duct section 10A, 10B comprises an inner duct passage 12 having a top wall 14, bottom wall 16, sidewall 18 and sidewall 20. In this embodiment of the invention, the top wall 14, bottom wall 16, sidewall 18 and sidewall 20 are formed of an insulation material such as a foam insulation material disposed between two foil sheets. One representative insulation material is a foam panel branded Kool Duct® ducting system available from Kingspan Insulation Limited and PTM Manufacturing LLC. The air circulation duct sections 10A, 10B of the air ductwork system passageway 100 have inner duct passageways of insulation material only, and without traditional metal ductwork.

Referring to FIGS. 5 and 6, the air circulation duct section 10B, inner duct passageway 12 has a top wall 14, bottom wall 16, sidewall 18 and sidewall 20. The inner surfaces of these walls define the air passageway. The opposite surfaces of these walls are surrounded by solid insulation in the form of top layer 24, bottom layer 26, side layer 28 and side layer 30. In the embodiment shown, the layers 24, 26, 28 and 30 are joined to opposite surfaces of walls 14, 16, 18 and 20 with double-sided adhesive tape. One representative double-sided tape is 1.5 inch wide tape sold by Venture under designation 1163/74-T-766.

Referring now to FIG. 6, the layers 24, 26, 28 and 30 of solid insulation may have the same thickness and length, but may have different widths. In the embodiment shown in FIG. 6, the top layer 24 and bottom layer 26 have a longer width than the side layers 28, 30. Portions of the widths of the top layer 24 and bottom layer 26 thus extend beyond the width of the top wall 14 and bottom wall 16 respectively. These portions contact and overlap the side edges of the side layers 28, 30.

The solid insulation layers may be a suitable insulation board, such as insulation board with an R-6 or R-8 insulation rating value. The layers 24, 26, 28 and 30 may be of the same insulation rating, or of different insulation rating. In one embodiment, the solid insulation layers comprise KoolTherm® board available from PTM Manufacturing LLC with a thickness of 0.81 inch ( 13/16 inch) and an insulation rating of R-8. Optionally, the side edges and end edges of the solid insulation layers may be covered with a moisture barrier 74, such as foil tape. One such tape is a 3-inch wide adhesive foil tape.

An external jacket may be formed over the solid insulation layers 24, 26, 28 and 30. The external jacket preferably comprises a material suitable to withstand weather effects of sunlight, rain, ice and snow. One suitable material for the jacket is a lightweight metal, such as aluminum. In one embodiment, the external jacket is formed with an aluminum metal sheet having a thickness of about 0.032 inch. Optionally, the aluminum metal sheet may be embossed to form a surface pattern therein.

In one embodiment, as shown in FIGS. 5 and 6, the external jacket comprises four jacket sections 32, 42, 48 and 54. First jacket 32 is joined to the top outer surface of top layer 24, such as with double-sided adhesive tape. First jacket 32 has a first right angle flange 34 at one side edge and a second right angle flange 36 at the opposite side edge. A first rib or channel 38 is formed in the first right angle flange 34. A second rib or channel 40 is formed in the second right angle flange 36.

Second jacket 42 is joined to the bottom outer surface of bottom layer 26, such as with double-sided adhesive tape. Second jacket as shown in FIG. 6 does not have any angled flanges at its side edges.

Third jacket 48 is joined to the outer surface of sidewall 28, such as with double-sided adhesive tape. Third jacket 48 has a right angle flange 50 at one side edge. In this embodiment, the opposite side edge of the third jacket 48 does not have an angled flange. A rib or channel 52 is formed in the right angle flange 50.

Fourth jacket 54 is joined to the outer surface of sidewall 30, such as with double-sided adhesive tape. Fourth jacket 54 has a right angle flange 56 at one side edge. In this embodiment, the opposite side edge of the fourth jacket 54 does not have an angled flange. A rib or channel 58 is formed in the right angle flange 56.

In one method, in a first step, the second jacket 42 is attached to the bottom layer 26 with double-sided adhesive tape. Then, in next steps, the third jacket 48 and fourth jacket 54 are attached to their respective sidewall layers 28, 30 with double-sided adhesive tape. The right angle flanges 50, 56 are positioned in overlapping relation over the side edges and a portion of the outer surface of second jacket 42. Lastly, the first jacket 32 is attached to the top layer 24 with double-sided adhesive tape. The right angle flanges 34, 36 of the first jacket 32 are positioned in overlapping relation over the side edges of the third jacket 48 and fourth jacket 54 respectively. A sealant or grout is applied to or placed inside the ribs or channels 38, 40, 52, 58 to join the edges of the external jacket sections to one another. The sealant or grout forms a barrier to restrict air and moisture from penetrating through the external jacket formed from first jacket 32, second jacket 42, third jacket 48 and fourth jacket 54 sections. Thus, the air circulation duct section 10 construction is weather-tight, making it suitable for outdoor use, as well as indoor use.

Two air circulation duct sections 10A, 10B are joined together at a joint to form an air duct system passageway 100. Referring now to FIGS. 2-5, two air circulation duct sections 10A, 10B are positioned in end to end relation for joining the ducts together. In a first step, shown in FIG. 3, slidably engagable sleeves 102, sometimes called bayonets, are inserted onto receiving flanges 96, 98 extending from end edges of the inner duct passage 12. The connection between the slidably engageable sleeves 102 and the flanges 96, 98 holds the ends of the air circulation duct sections 10A, 10B together in end to end relation whereby the air circulation system passageway is defined along the lengths of the air circulation duct sections 10A, 10B so joined. While just two air circulation duct sections 10A, 10B are shown in the Figures, it is contemplated that an air circulation passageway of any desired length may be formed by joining multiple air circulation duct sections together. An air duct passageway may include multiple air circulation duct sections joined together in series.

The joint openings between the air circulation duct sections 10A, 10B are next covered with sections of filler insulation 106. As shown in FIG. 4, the top layer of filler insulation 106 a, and the bottom layer of filler insulation 106 b, have longer lengths than the side layers of filler insulation 106 c, 106 d. Hence, the lengths of top layer and bottom layer of filler insulation 106 a, 106 b overlap the ends of the side layers of filler insulation 106 c, 106 d. In one embodiment, the filler insulation 106 may comprise KoolTherm® board with a thickness of 0.875 inch and an R6 insulation rating, or may comprise polyisocyanurate foam disposed between foil sheets with suitable thickness and insulation rating.

Referring now to FIG. 5, a closure band 110 encircles the joint and covers the filler insulation 106. The closure band 110 may be of a material suitable to withstand weather effects of sunlight, rain, ice and snow. One suitable material for the closure band 110 is a lightweight metal, such as aluminum. In one embodiment, the closure band is formed with an aluminum metal sheet having a thickness of about 0.032 inch. The closure band 110 in one preferred embodiment has a rib or channel 112, 114 formed along each side edge.

The closure band 110 is joined to the external jackets of air circulation duct sections 10A, 10B first with lengths of gasket tape 70, 72. The closure band 110 may be made in sections, such as 8 foot long sections, that have beads or grooves along each longitudinal side or near to each longitudinal side. The gasket tape may comprise a one inch wide butyl gasket tape pre-joined to the bottom surface of the closure band 110 and covered by release paper (not shown). Two lengths of gasket tape 70, 72 may be applied in substantially parallel relation along the length of the closure band, with one length of tape adjacent or near each longitudinal side of the closure band. As a first step, the release paper may be removed to expose the adhesive of the gasket tape for adhesively securing the closure band to the external jackets. In addition, the closure band 110 is joined to the external jackets of air circulation duct sections 10A, 10B with fasteners 60, 62, such as screws or bolts and seal washers. In one embodiment, the fasteners 60 are #10 stainless steel self-tapping screws (0.75 inch), and the washers 62 are weather seal washers, and the fasteners 60, 62 are placed on 6-inch centers around the full circumference of the duct system. In the embodiment shown in FIGS. 5 and 6, the fasteners 60 (screws) are positioned so as to penetrate through the butyl gasket tape 70, 72. Moreover, the closure band 110 is joined to the external jackets of air circulation duct sections 10A, 10B by applying a full bead of sealant or grout 80 along the side edges of the closure band 110 and into the ribs or channels 112, 114. The sealant or grout 80 extends around the full circumference of the duct system and forms a barrier to restrict moisture from penetrating through the closure band and the external jackets at the joint between air circulation duct sections 10A, 10B.

While embodiments of this invention have been shown and described, it will be apparent to those skilled in the art that many more modifications are possible without departing from the inventive concepts herein. The invention, therefore, is not to be restricted except in the spirit of the following claims. 

We claim:
 1. A method for making an insulated ductwork system without metal ductwork by joining together air circulation duct sections of insulation material, comprising: (1) arranging a first air circulation duct section having a first end and a second end in end to end relation with a second air circulation duct section having a first end and a second end, wherein the first air circulation duct section comprises an inner duct air passageway formed with a first insulation material having a top wall, a bottom wall and two opposed sidewalls; a least a first layer of solid insulation, said first layer having a top surface and an opposite surface, with its opposite surface joined to the top wall of the inner duct air passageway; a first jacket joined to the top surface of the first layer of solid insulation; at least a second layer of solid insulation having a top surface and an opposite surface, with its opposite surface joined to the bottom wall, a second jacket joined to the top surface of the second layer of solid insulation; at least a third layer of solid insulation having a top surface and an opposite surface, with its opposite surface joined to one sidewall, a third jacket joined to the top surface of the third layer of solid insulation; at least a fourth layer of solid insulation having a top surface and an opposite surface, with its opposite surface joined to the other sidewall, a fourth jacket joined to the top surface of the forth layer of solid insulation; wherein said jackets, insulation layers and inner duct air passageway together form the first air circulation duct section, and at least one receiving flange extending from the first end of the first air circulation duct section; (2) joining the first end of the first air circulation duct section to the first end of the second air circulation duct section by sliding a sleeve to engage the at least one receiving flange extending from the first end of the first air circulation duct section with at least one receiving flange extending from the first end of the second air circulation duct section to join the first ends of the first air circulation duct section and the second air circulation duct section together in abutting end to end relation; (3) disposing filler insulation over the sleeve; and (4) joining a closure band disposed over the filler insulation with tape, fasteners or sealant, or tape, fasteners and sealant in combination to the first air circulation duct section and to the second air circulation duct section.
 2. The method of claim 1, wherein the first layer of solid insulation, the second layer of solid insulation, the third layer of solid insulation and the fourth layer of solid insulation of the first air circulation duct section comprise insulation material disposed between metal foil sheets.
 3. The method of claim 1, wherein one or more of the first jacket, the second jacket, the third jacket and the fourth jacket comprise an angled flange along its length along at least one side.
 4. The method of claim 3, further comprising fastening the angled flange of one jacket in overlapping relation to an adjacent jacket.
 5. The method of claim 4, further comprising applying grout or sealant into a channel defined in the angled flange of one jacket to join the angled flange of the one jacket in overlapping relation to the adjacent jacket.
 6. The method of claim 1, further comprising joining the closure band to at least one of the jackets with adhesive tape.
 7. The method of claim 1, wherein the at least one closure band defines a rib or channel at or near its side edge that is adapted to receive sealant.
 8. The method of claim 1, wherein the first, second, third and fourth jackets are formed of metal. 